Variation of the in-plane penetration depth as a function of doping thin films on: Implications for the overdoped state

Abstract

Normal-state properties, such as the resistivity (Formula presented) and the Hall coefficient (Formula presented), structural properties, such as the c axis and in-plane lattice parameters, and superconductive properties, such as the critical temperature (Formula presented), the penetration depth (Formula presented), and the thermal activation energy for flux flow ΔU, are reported for c-axis (Formula presented)(Formula presented)(Formula presented) films. These parameters have been measured as a function of doping in the range from heavily underdoped to heavily overdoped. The structural data indicate a 0.3% compression of the c-axis parameter and a corresponding 0.3% expansion of the in-plane lattice parameters as compared to bulk values, which explains the overall reduced critical temperature of these thin films. As the dopant content is increased, maximum values for (Formula presented), ΔU, and (Formula presented) are observed close to optimum doping, while (Formula presented) and (Formula presented) decrease monotonically. © 1996 The American Physical Society.